1. Field of the Invention
The air treating apparatus may take the form of an evaporator cooler, a cooling tower, a humidifier for use with an air system and especially adapted for installation on a forced air furnace, a free standing humidifier for use in a room, a window humidifier or other kinds of similar air-conditioning or treating apparatuses.
2. Description of the Prior Art
Apparatuses utilizing water distribution means include the structures shown in the following U.S. Patents: No. 3,975,470 to Lewis O. Engel, dated Aug. 17, 1976 and assigned to the assignee of record; No. 2,281,799 to O. E. Quave, dated May 5, 1942; No. 2,809,820 to F. D. Stoops, dated Oct. 15, 1957; No. 3,193,259 to J. M. Liebmann, dated July 6, 1965; No. 3,199,846 to R. F. Durham et al, dated Aug. 10, 1965; No. 3,318,587 to P. E. McDuffee, dated May 9, 1967; 3,401,681 to P. E. McDuffee, Sr. et al, dated Sept. 17, 1968; No. 3,464,401 to W. L. McGrath, dated Sept. 2, 1969; No. 3,497,453 to A. Yurden, dated Feb. 24, 1970; No. 3,570,822 to C. D. Peterson, dated Mar. 16, 1971; and other patents cited therein.
Underwriters' Laboratories, Inc.'s "Standard For Electric Fans", UL 507, effective January 1, 1973, provides on page 8 thereof for backflow prevention in evaporative coolers. Paragraph 5.1 provides that an air gap shall be provided to prevent backflow into a water supply system from the storage reservoir of an evaporative cooler. Paragraph 5.2 provides that the design of an air gap fitting shall assure that an unobstructed minimum vertical distance of one inch or two inlet pipe inside diameters, whichever is greater, will be permanently maintained through the free atmosphere between the lowest opening of the water inlet device supplying water to the evaporative cooler and the flood level rim of the reservoir receiving the water.